Biology Cellular Respiration Adenosine Triphosphate Files/Biology/cell respiration, ATP.pdf · energy in a process called metabolism ... independent cells such as bacteria. ... are

Cellular Respiration

&

Adenosine Triphosphate

General Education Program

Biology

Presented by:Dr. Shaimaa Nasr Amin

Lecturer of Medical Physiology

• Energy is the foundation of all life. In

humans energy originates within the human

cell. It is there that numerous bio-chemical

reactions take place to generate cellular

energy in a process called metabolism

• Human metabolism/cellular energy is the

limiting factor in determining the quality of

health an individual will experience.

• Optimal metabolism results in the 100

trillion human cells to function at peak

performance.

• There are two primary types of cells

found in nature:

1. Eukaryotic cells – found in multi-cellular

organisms such as fungi, plants, and

animals (humans).

2. Prokaryotic cells - are primitive

independent cells such as bacteria.

• The major difference between prokaryotes

and eukaryotes is that eukaryotic cells

contain membrane bound organelles in

which specific metabolic activities take

place. The defining organelles that set

eukaryotic cells apart from prokaryotic cells

are the nucleus and mitochondria.

• The nucleus is the control center of the cell

housing its nuclear deoxyribonucleic acid

(nDNA), which contains the information

needed to keep a cell operating and

working properly.

MITOCHONDRIA

• The source of cellular

energy for all eukaryotic

biochemical reactions,

comes from one of the

cell’s organelles called

the mitochondria.

• Mitochondria are known as the cell’s “power

house” where cellular energy is produced in

the form of a molecule called – adenosine

triphosphate (ATP).

• Depending on the tissue, mitochondria can

number anywhere from a couple of dozen

(neuron) to several thousand (heart) per cell.

• Another interesting fact – mitochondria

have their own set of DNA –mitochondria

DNA (mtDNA), which is inherited from the

mother.

• Mitochondria are made from a combination

of nDNA & mtDNA

ATP PRODUCTION:

CELLULAR RESPIRATION

• Carbohydrates, lipids (fats), and proteins are

the major constituents or nutrients of foods

and serve as fuel for the human body.

• More specifically, it is the end products of

digestion – which breaks down these macro

nutrients into smaller nutrients – that are the

true fuel sources for the body’s 100 trillion

cells.

• The major absorbed end products of food

digestion are glucose (from carbohydrates);

short, medium and long-chain fatty acids

(from lipids); and amino acids (from

protein).

• All three classes of these nutrients can

serve as fuel sources for the mitochondria

to produce cellular energy in the form of

ATP

Adenosine Triphosphate (ATP)

• ATP is a high energy nucleotide and is

considered the cell’s “energy currency” which

provides the needed energy for the cell’s

many metabolic bio-chemical functions.


• ATP is a molecule

which is made up of

three phosphate

groups and an

adenosine group

(ribose and adenine).


• When the “high-energy” bond between the

second and third phosphate are broken a

substantial amount of energy is liberated


• The major metabolic bio-chemical pathway

which is responsible for the production of

ATP/cellular energy is called cellular

respiration.

• The sole purpose of cellular respiration is

to break down glucose, fatty acids and

small amounts of amino acids into ATP.

• Cellular respiration takes place via a long step

by-step process of enzymatic reactions.

These enzymatic reactions can be divided

into two main categories:

• 1. Anaerobic Respiration.

• 2. Aerobic Respiration


Anaerobic Respiration

• are the enzymatic reactions

that DO NOT require

oxygen.

• This includes the metabolic

pathway of glycolysis and

fermentation which occurs in

the cytoplasm of the human

cell

. Aerobic Respiration

• are the enzymatic reactions

that DO require oxygen.

This includes the metabolic

pathways of pyruvate

oxidation, Krebs cycle and

oxidative phosphorylation

(electron transport chain &

chemiosmosis) which all

occur in the mitochondria.


ANAEROBIC RESPIRATION


• Glycolysis

• The first stage of cellular respiration is

known as glycolysis.

• This stage is unique to glucose metabolism

which takes place in the cytoplasm of the

cell and does not require oxygen.

• Through a series of biochemical enzymatic

reactions the process of glycolysis breaks

down glucose to pyruvate/pyruvic acid.


• Glycolysis

• Glycolysis also generates 2 molecules of

ATP and 2 molecules of NADH. NADH is the

reduced form (gained hydrogen atoms) of

nicotinamide adenine dinucleotide (NAD).


• Glycolysis

• NAD is a co-enzyme which is derived from

the vitamin – niacin (B3). Once reduced

NADH acts as an electron carrier and will be

transferred to the mitochondria and utilized in

the electron transport chain to assist in

producing additional molecules of ATP.


• Fermentation

• In the continual absence of oxygen (after

glycolysis has been completed) the process

continues to follow the anaerobic pathway

and a process called fermentation.


• Fermentation

• There are several types of fermentation, but

the two most common types are lactic

acid/lactate fermentation and alcohol

fermentation.


• Fermentation

• In fermentation the pyruvate/pyruvic acid

molecules, which are toxic to the cell and

cannot enter the mitochondria due to the lack

of oxygen, are converted by enzymes into

waste products.

• Also fermentation does not produce any

additional energy/ATP. .


• Fermentation

• Lactic acid fermentation takes place in some

fungi and some bacteria like Lactobacillus

acidophilus (yogurt).


• Fermentation

• In humans, lactic acid fermentation takes

place in the muscles during times of

strenuous exercise or great exertion. Under

these conditions the oxygen supplied by the

lungs and blood system cannot get to the

cells fast enough to keep up with the muscles’

demands.


• Fermentation

• At this point the muscle cells will switch over

to lactic acid fermentation, by converting

pyruvate into lactic acid via the enzyme lactic

acid dehydrogenase (LDH). The build-up of

lactic acid can cause cramping and a burning

sensation in the over worked muscles as well

as sore muscles the following day until the

lactic acid is washed out of the system.


• The glycolysis-fermentation pathway is

important to muscle cells, by producing

“some” ATP, during times when oxygen is in

short supply. However, this process cannot be

applied to the nerve cells/neurons in the

nervous system.


• This is because of one major difference

between nerve cells and muscle cells which is

nerve cells cannot switch to lactic acid

fermentation if oxygen is low.


• The nervous system is totally dependent, from

minute-to-minute and second-to-second, on

the oxygen delivered by the blood. Therefore,

the lack of proper oxygen levels in the brain

will result in impaired brain functioning

AEROBIC RESPIRATION

Aerobic Respiration

• Pyruvate Oxidation/Transition Reaction:

• After the completion of glycolysis and the

production of pyruvate - if oxygen is

present, pyruvate enters the mitochondria

and forms acetyl-coA during the second

stage called - pyruvate oxidation or

transition reaction. In this stage an acetyl

group is produced by cleaving off a carbon

atom from pyruvate.

Aerobic Respiration


• The acetyl group is then bonded with

coenzyme A (CoA) thereby forming acetyl-

CoA. CoA is synthesized in the body from

pantethine and cysteine.

Aerobic Respiration


• Though glycolysis is the primary source of

acetyl-coA formation, acetyl-coA is also

associated with the metabolism of fatty

acids ketones and amino acids.

• Since acetyl-coA is common to all four

pathways, it is sometimes called the

“crossroads compound”. Also produced

in this pathway are 2 molecules of NADH.

Aerobic Respiration

• Krebs/Citric Acid Cycle/TCA Cycle

• Once formed, acetyl-coA will enter into the

Krebs/citric acid cycle/TCA cycle which is a

“circular” series of enzymatic reactions which

take place in the matrix/inner compartment of

the mitochondria.

Aerobic Respiration


• The result of the Krebs cycle is an additional 2

molecules of ATP , 6 molecules of NADH and

2 molecules of another electron carrier called

FADH2.

Aerobic Respiration


• FADH2 is the reduced form (gained hydrogen

atoms) of flavin adenine dinucleotide (FAD).

FAD is a co-enzyme which is derived from the

vitamin – riboflavin (B2) and once reduced it

will also be used in the electron transport

chain to assist in producing additional ATP.

Aerobic Respiration

• Oxidative Phosphorylation: The Electron

Transport Chain & Chemiosmosis

• The electron transport chain is a series of five

protein complexes (I, II, III, IV, V) within the

cristae/inner mitochondrial membrane

Aerobic Respiration



• And by means of a very complicated series of

events the electron carriers -NADH and

FADH2 produced during the earlier stages of

glycolysis, pyruvate oxidation, Krebs cycle are

now used to create a high gradient of hydrogen

atoms in the outer mitochondrial compartment.

Aerobic Respiration



• This high gradient forces the hydrogen atoms to

cross back through the cristae into the matrix.

This process of transferring hydrogen atoms

across the cristae is called chemiosmosis and

occurs via a special membrane protein called

ATP Synthase (complex V).

Aerobic Respiration



• ATP synthase is the machinery or protein

molecule that is responsible for actually

producing ATP from adenosine diphosphate

(ADP) and phosphate.

Aerobic Respiration



• This entire process, that takes place through the

electron transport chain, and chemiosmosis

generates an additional 34 molecules of ATP

and is referred to as oxidative phosphorylation

ATP Tally: Glucose

• ATP the “energy currency” of the cell which

was produced by means of a process called

cellular respiration. Through this process it

was noted that ATP was formed at various

stages along with the high energy carriers –

NADH and FADH2

• NADH and FADH2, are major contributors

to the production of ATP via the creation of

a hydrogen gradient in the electron

transport chain. During this process each

NADH (indirectly) yields 3 ATP while each

FADH 2 (indirectly) yields 2 ATP.

• the total amount of ATP produced per one

molecule of glucose is:

ATP Production: Beta Oxidation

• Normally, 60% to 90% of the energy required

for contraction of the heart is derived from

the oxidation of fatty acids.

• Also, if for some reason adequate amounts

of glucose are not available such as - during

times of stress, long periods between meals,

and fasting - the body cells can catabolize

(break down) stored fats/lipids and even

proteins for energy.

Lipid/Fatty Acid Catabolism

• Lipids provide highly efficient energy storage,

storing much more energy for their weight

than carbohydrates like glucose. Lipids are

primarily stored in adipose tissue (body fat)

as triglycerides which are composed of a

glycerol backbone with three fatty acids

attached.


• Triglycerides form fatty droplets that exclude

water and take up minimal space.

• Fatty acids are also more highly reduced than

carbohydrates, so they provide more energy

during oxidation.


• The efficiency of energy storage of lipids is

probably an important reason why animals

(humans) store most of their energy as fats

and only a small amount of energy as

carbohydrates.


• When needed as an energy source the fat

reserves are mobilized via a process called

lipolysis.

• Lipolysis largely occurs in adipose tissue

where glycerol is cleaved off of the fatty acids.

Once completed the fatty acids and glycerol

are then released from the adipose tissue into

the blood and transported to the energy

requiring tissue.


• In the cell glycerol – a sugar alcohol - is further

converted into one of the intermediate

products of glycolysis – glyceraldehyde

phosphate – and then to pyruvate.


• Glycerol makes up only 5% of the lipid

metabolism. The remaining 95% of lipid

metabolism takes place when the fatty acids

enter the mitochondria’s Krebs cycle.

Carnitine Palmitoyltransferase System

(CPT)

• Before fatty acids can enter the mitochondria

they need to be “activated”.

• The activation of fatty acids takes place in the

cell’s cytosol where the enzyme acyl-CoA

synthetase (ACS) - located on the “outer

surface” of the outer mitochondria membrane -

links the sulfhydryl group of Coenzyme A

(CoA) to a fatty acid.


(CPT)

• ATP drives the formation of this linkage to

form a new compound called Acyl-CoA .

• Once activated the short chain fatty acid acyl-

CoA’s (<6 carbon atoms long) and medium

chain fatty acid acyl-CoA’s (6-12 carbon atoms

long) can freely diffuse into the mitochondria

to be oxidized via a process called beta-

oxidation.


(CPT)

• However, the long chain fatty acid acyl-CoA’s

(>12 carbon atoms long) are unable to diffuse

into the mitochondria and therefore must be

transported in.


(CPT)

• The transport of long chain fatty acids into

mitochondria is accomplished by the carnitine

palmitoyltransferase system (CPT system -

CPTI & CPTII), sometimes referred to as the

carnitine shuttle.


(CPT)

• The CPTI enzyme, which is bound to the

“inner surface” of the outer mitochondrial

membrane,exchanges coenzyme A for

carnitine on the long chain fatty acid acyl CoA

molecule.

• The bonding of carnitine forms a fatty acid-

carnitine conjugate called acyl-carnitine.


(CPT)

• Acyl-carnitine is then shuttled across the inner

mitochondrial membrane by a transporter

protein/enzyme called the carnitine

acylcarnitine translocase (CACT).


(CPT)

• Once acyl-carnitine has been transported into

the matrix of the mitochondria CPTII

exchanges carnitine for CoA, thereby, once

again producing a long chain fatty acid acyl-

CoA.


(CPT)

• Now in the mitochondria matrix, the long chain

fatty acid acyl- CoA can be oxidized via a

beta-oxidation. The removed carnitine is

transported back through the CACT to be re-

used..

Beta Oxidation

• Beta-oxidation is the process whereby all

activated fatty acid (short, medium & long

chain) acyl-CoA’s are oxidized, via a repeating

four-step enzymatic cycle.

Beta Oxidation

• In each four-step cycle, a fatty acid is

progressively shortened by having two of its

carbon atoms cleaved off.

• The remaining fatty acid chain re-enters the

beta oxidation pathway resulting in another

pair of carbon atoms cleaved off.

Beta Oxidation

• This process is repeated until all the carbon

atoms in the original fatty acid acyl-CoA are

gone.

• The cleaved pairs of carbon atoms are used to

produce acetyl groups which are then linked

with coenzyme A molecules to produce

molecules of acetyl-CoA.

Beta Oxidation

• acetyl-CoA is the entry point into the Krebs

cycle where ATP, NADH and FADH2 are

produced.

• Also, during each four-step enzymatic cycle,

the electron carriers NAD+ and FAD are

reduced to produce (1) NADH and (1) FADH2

which are transported to the electron transport

chain to assist in producing ATP.

ATP Tally: Fatty Acids

• The number of ATP produced from the

breakdown of fatty acids depends on which

fatty acid is utilized.

• However, the following example of

palmitate/palmitic acid, a common saturated

fat found in plants and animals, will give a

good example of why fatty acids are a highly

concentrated source of energy.

ATP Tally: Fatty Acids

• Palmitate is a 16 carbon atom and will

therefore cycle through the beta oxidation

pathway 7 times.

• Thereby forming 7 NADH’s, 7 FADH2’s and 7

acetyl-CoA’s.

• Plus the last two remaining carbon atoms will

also be converted to acetyl CoA. Making the

total number of acetyl-CoA produced to be 8.

ATP Production: Ketogenisis

• Ketogenesis & Ketosis

• Ketosis is simply the accumulation of

ketones/ketone bodies in the body. This is a

controversial subject with the debate centered

on whether or not ketosis is potentially

dangerous or even beneficial for some people.



• On one side of the issue it is claimed that

ketones are formed due to the result of a

restricted or low intake of carbohydrates.

• This occurs during times of starvation, fasting,

severe dieting or when glucose is not fully

utilized as in diabetes. Due to such a restricted

carbohydrate intake, the body converts to the

oxidation of more fats for energy.



• This shift occurs mainly because the entry of

acetyl-coA into the Krebs cycle depends on

the availabilityof oxaloacetic acid (1st step in

Krebs cycle), which becomes deficient in a low

carbohydrate diet.



• This scenario of low oxaloacetic acid levels

will in turn cause fatty acid oxidation to be

incomplete thereby causing an excess of

acetyl-coA to accumulate in the cells. The

excess acetyl-coA is transported to the

• liver where it is converted to ketones via a

process called ketogenesis



• Since most ketones are acidic, in certain

people ketosis can lead to metabolic acidosis

or ketoacidosis which is an increase in blood

and tissue acidity which can be dangerous.



• The body eliminates most ketones (i.e.

acetone) by excreting them through the urine

as well as the breath. Ketones excreted

through the breath give a person’s breath a

sweet, fruity smell that has been likened to the

smell of nail varnish.



• The physiological significance of these ketone

bodies takes the form of ATP production.



• There is limited transport of fatty acids across

the blood-brain barrier, which explains why

fatty acids are not a significant fuel source for

the brain. Ketone bodies, however, can cross

the blood brain barrier and can therefore be an

alternative source of energy for the brain.



• Unlike glucose, the uptake of ketone bodies

occurs via the family of monocarboxylate

transporters (MCTs), which are not insulin

mediated.”



• MCT proteins enable ketones to pass readily

through the blood-brain barrier. Many types of

peripheral cells, including brain cells, not only

use glucose, but also use ketones to produce

acetyl-CoA.”



• ATP is produced by ketones when the ketone

bodies – beta-hydroxybutyrate (BHB) and

acetoacetate (AcAc) enter the mitochondria

and are acted upon by several enzymes.



• Ketolysis – the splitting up of ketones – takes

place first when 3-oxoacid-CoA transferace

(OCT) adds coenzymeA to AcAc, which is then

split into two molecules of acetyl-CoA by

acetoacetyl-CoA thiolase (ACT). The acetyl-

CoA molecules then enter into the Krebs/TCA

cycle



• In the liver, much of the acetyl CoA generated

from beta-oxidation of fatty acids is used for

synthesis of the ketone bodies acetoacetate

and beta-hydroxybutyrate, which enter the

blood.



• In skeletal muscles and other tissues, these

ketone bodies are converted back to acetyl-

CoA, which is oxidized in the TCA cycle to

produce ATP.

• ketones are basically water soluble fats

which dissolve in blood. And are a source

of energy for many tissues including the

muscles, brain and heart.

• Though ketones can’t totally replace all the

sugar required by the brain, they can

replace a good chunk of it.

ATP Production: Protein/Amino Acid

Catabolism

• The first step in protein catabolism is to

digest protein molecules into individual

amino acids. Once this is done the removal

of the amino group (NH2) is required and

takes place in the liver via a process called

deamination. The removed amino group is

converted to ammonia (NH3).


Catabolism

• Ammonia is highly toxic and is further

converted in the liver to urea and then

excreted from the body via the kidneys.


Catabolism

• Once the amino group is removed the

remaining carbon skeleton – a keto acid -

can enter the cellular respiration cycle

either as pyruvic acid (50%), acetyl CoA

(25%) or enter directly into the Krebs/citric

acid cycle (25%) to generate ATP (different

amino acids go through different pathways).


Catabolism

• Catabolism of amino acids is not a practical

source of quick energy and is typically only

used in starvation situations.

•


Catabolism

• Proteins are harder to break apart than

carbohydrates or lipids, their catabolism

generates toxic waste products (ammonia),

and they are the structural and functional

parts of every cell, and thus tend to only be

used when no other energy source is

available.

ATP Production: ATP Turnover

• Regardless of the source of ATP –

glycolysis, beta-oxidation, Krebs cycle,

oxidative phosphorylation –ATP needs to

be “turned over” so that it is re-used over

and over. This is to supply the body with

the huge amounts of ATP it demands, of

which cannot be produced in such volumes

from scratch by normal metabolic

pathways.

ATP Production: ATP Turnover

• The turnover process takes place naturally

by means of a protein called adenine

nucleotide translocator (ANT) or ATP-ADP

translocase.

Adenine Nucleotide Translocator

(ANT)/ATP-ADP Translocase

• The production of ATP, via ATP synthase,

occurs on the inside of the mitochondrial

inner membrane – in the matrix. But most

of the cellular ATP usage is required

outside the mitochondria - in the cytosol.

• Therefore ATP needs to be transported

from the mitochondria’s matrix to the cell’s

cytosol.



• This is accomplished through a special

protein called adenine nucleotide translocator

(ANT) or sometimes referred to as the ATP-

ADP translocase which is located on the

inner membrane of the mitochondria.



• ANT is the most abundant protein of the inner

mitochondrial membrane and is the most

active enzyme in animal (human) cells.



• Once transported into the cytosol, ATP

undergoes hydrolysis via the enzyme

• ATPase. ATPase breaks the phosphate bonds

and thereby releasing energy to be used for the

cells many biochemical functions.



• This process also results in the formation of a

new molecule -adenosine di-phosphate (ADP)

and a phosphate molecule. ANT will now be

used to transport the ADP molecule back into

the matrix for reprocessing.



• ANT simultaneously transports both ATP and

ADP. For each ATP molecule transported out of

the matrix, one molecule of ADP is transported

into the matrix.



• Once in the matrix ADP and phosphate are re-

synthesized via ATP synthase to produce a new

molecule of ATP starting the cycle all over.

ATP Production: The ATP–CP System

• The ATP-CP System. Unlike the normal

metabolic pathways this pathway or system

is exclusive to muscle (includes cardiac),

brain and eye cells only. The ATP-CP system

is a non-lactic acid producing, anaerobic

(without oxygen) system whose primary use

is for quick short-acting bursts of energy.

The ATP–Creatine Phosphate

(CP)/ATP–Phosphocreatine (PCr)

System

• When the body is at rest energy needs are

fulfilled by aerobic catabolism because the

low demand for oxygen can easily be met

by oxygen exchange in the lungs and by

the oxygen carried to the muscle by the

cardiovascular system.



System

• If physical activity is initiated, the energy

requirements of contracting muscle are met

by existing ATP.

• However, stores of ATP in muscle are limited,

providing enough energy for only a few

seconds. If the physical activity continues

ATP levels diminish as it is converted to ADP.



System

• Luckily, the body has a small reservoir of

creatine phosphate(CP)/phosphocreatine

(PCr) which can be used to quickly

regenerate ADP into ATP. Creatine

phosphate is nothing more than a molecule

of creatine with a phosphate molecule

bonded to it.



System

• This process is catalyzed by the enzyme

creatine kinase (CK), and the reaction is

reversible. The enzyme can either add a

phosphate to creatine to make creatine

phosphate, or remove one to make creatine,

depending on the needs of the cell



System

• This process is catalyzed by the enzyme

creatine kinase (CK), and the reaction is

reversible. The enzyme can either add a

phosphate to creatine to make creatine

phosphate, or remove one to make creatine,

depending on the needs of the cell



System

• Creatine phosphate is found in muscle, brain

and eye cells in the amount of 4 to 6 times

greater than that of ATP. Thus most energy is

stored at these sites in creatine phosphate

pools.



System

• Because only one enzymatic reaction is

involved in this energy transfer, ATP can be

formed rapidly (within a fraction of a second)

by using creatine phosphate.



System

• At rest, muscle fibers produce more ATP than

is required by the body. This excess ATP is

used to synthesize creatine phosphate.

• The enzyme creatine kinase catalyzes

muscles fibers to break down excess ATP

and transfer a phosphate group to creatine,

forming creatine phosphate and ADP.



System

• During contraction, muscle fibers transfer the

phosphate group from creatine phosphate to

ADP, forming ATP.



System

• All though the ATP-CP system creates ATP

almost instantly, it does have its limits.

• In that in can only produce about 15

seconds worth of physical activity. Although

this may seem like a very limited amount of

time, creatine phosphate provides the

muscles with ATP before aerobic respiration

can take over.



System

• The ATP-CP system is active at the

beginning of all forms of activities but is

especially important in high intensity

exercises that require short bursts of energy.



System

• All though the ATP-CP system creates ATP

almost instantly, it does have its limits. In that

in can only produce about 15 seconds worth

of physical activity. Although this may seem

like a very limited amount of time, creatine

phosphate provides the muscles with ATP

before aerobic respiration can take over



System

• The ATP-CP system is active at the

beginning of all forms of activities but is

especially important in high intensity

exercises that require short bursts of energy.

The Methylation Connection

• Methylation is one of the most common

metabolic functions of the body, occurring in

the order of a billion times per second. It is the

process by which a methyl group (CH3) is

transferred from one molecule (a methyl

donor) to another (which becomes

'methylated').


• over 100 different biochemical reactions in the

body, which are catalyzed by

methlytransferase enzymes, influencing such things as:

- Energy (co-q10, carnitine, creatine)

- Cell membrane growth & repair (myelin,

phospholipids)

- Neurotransmitters (adrenaline, nor-

adrenaline, dopamine, serotonin, histamine)


• over 100 different biochemical reactions in the

body, which are catalyzed by

methlytransferase enzymes, influencing such things as:

- Hormones (thyroid, adrenal, melatonin)

- Immunity (T-cells, autoimmunity, histamine,

TH1/TH2 balance, viral DNA, NK cell function)

- DNA & RNA

- Detoxification (sulfur metabolism, glutathione,

redox)


• The main methyl donor in the body is called

S-adenosylmethionine (SAMe). Levels of

SAMe are maintained by a basic cellular

biochemical cycle, called the methylation

cycle. Whereby SAMe is synthesized from the

amino acid methionine.

Methylation & Coenzyme Q10

Synthesis

• Coenzyme Q10 (CoQ10) is a vital component

of the electron transport chain where it is

responsible for the transfer of electrons

between complex I, II & III.

• Without out CoQ10 there would be no ATP

production.

Methylation & Coenzyme Q10

Synthesis

• CoQ10 is a non-essential nutrient which is

naturally produced in the human body and

is synthesized from the amino acid tyrosine

and precursor molecules. Two of the final

steps in the biosynthesis of CoQ10 involve

methylation by SAMe

Methylation & Carnitine Synthesis

• Carnitine is responsible for the shuttling of

long chain fatty acids across the

mitochondrial membrane so they may be

used in the beta-oxidation system.


• Carnitine is a non-essential nutrient which is

naturally produced in the human body from -

the synthesis which begins with the

methylation of the amino acid lysine by

SAMe.


• After several more steps requiring

consecutive methylations and the interaction

of several enzymes, vitamins and minerals –

carnitine is produced in the body.

Methylation & Creatine Synthesis

• The ATP–creatine phosphate system is the

body’s energy reserve tank. Supplying

energy for quick short

• acting burst of energy.


• Creatine is a non-essential nutrient which is

naturally produced in the human body from

the amino acids glycine, aginine and

methionine. The synthesis of creatine occurs

primarily in the kidneys and liver.


• Once synthesized, creatine is transported in

the blood for use by muscle tissue, brain and

the eyes.

• Approximately 95% of the human body's total

creatine is located in muscle tissue.


• The synthesis of creatine, via methylation, is

the single greatest drain of the body’s methyl

reserves, consuming over 70% of the body’s

entire supply.

• Furthermore, given that the body’s methyl

reserves are limited in size, creatine

synthesis alone could potentially create a

state of methyl-deficiency.

Methylation Cycle & Adenosine

• Adenosine is a molecule, made up of

ribose and adenine, which form the back

bone to the all-important molecule this

report has centered on – adenosine tri-

phosphate (ATP), adenosine di-phoshpate,

(ADP), and adenosine mono-phosphate

(AMP)

Methylation Cycle & Adenosine

• Adenosine can be synthesized in the body

through a couple of pathways, but a key

pathway is through the methylation cycle. In

the methylation cycle SAMe is enzymatically

converted into an intermediate molecule

called S-adenosylhomocysteine (SAH). And

via a series of enzymatic activities SAH can

be converted to adenosine or any one of its

by products →AMP →ADP→ATP.

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Biology Cellular Respiration Adenosine Triphosphate Files/Biology/cell respiration, ATP.pdf · energy in a process called metabolism ... independent cells such as bacteria. ... are